[Ambulatory blood pressure profile during 48 hours in patients treated with chronic hemodialysis]

Hypertension is one of the severest cardiovascular risk factor in subjects affected by end-stage renal disease in chronic hemodialysis. The behavior of blood pressure between the first hemodialysis (day 1) and the next one (day 2) was studied in 24 untreated normotensive hemodialysis patients. Patients were between 34 and 83 years (mean age: 60 +/- 12 yrs) and were hemodialysed 3 x 4 hours a week, between 7 and 12 a.m. ABP was recorded at 15 minutes intervals between 7 and 22 hours, and 30 minutes intervals during the night, during 48 hours with a Spacelabs 90202 or 90207 device. The following results were observed: ABP is greater at day 2 (122/74 mmHg) than at the first (117/70 mmHg, p less than 0.001); that increase is not correlated with gaining weight during interdialytic period; after hemodialysis, blood pressure continues to fall during 2 or 3 hours until a level of 119 mmHg; low values continue during postdialysis and during the first night; the following day, ABP increases progressively during the morning and during the evening; before the second hemodialysis, the increase is suddenly faster; circadian rhythm is lost in 9/24 patients; in 17/24 patients, nocturnal decrease of BP is lower than 5%; age and ancientness of hemodialysis are the most important factor; rest blood pressure measured by physician before HD is continually higher than diurnal ABP (138/74 vs 121/73 mmHg, p less than 0.001), even if ABP is only analysed during one hour before the second hemodialysis (129/77 mmHg).

Antihypertensive effects of beta-blockers administered once daily: 24-hour measurements

Whole-day automated ambulatory blood pressure (BP) monitoring was used to assess the duration of the antihypertensive actions of the beta-blockers atenolol (50 to 100 mg; n = 20) and acebutolol (400 to 800 mg; n = 19) each given once daily at 9 AM. When compared with its pretreatment 24-hour average, atenolol decreased diastolic BP by 10 +/- 2 mm Hg (p less than 0.01) and systolic BP by 12 +/- 2 mm Hg (p less than 0.01). Acebutolol decreased the 24-hour diastolic BP by 11 +/- 1 mm Hg (p less than 0.01) and systolic BP by 13 +/- 2 mm Hg (p less than 0.01). More specifically, a comparison of the two drugs during the final 6 hours (3 AM to 9 AM) of the dosing interval showed that the mean decrease in diastolic BP of 10.2 +/- 1.5 mm Hg with acebutolol was greater (p less than 0.05) than the decrease of 6.2 +/- 1.3 mm Hg with atenolol. Moreover, this final 6-hour effect of atenolol was less (p less than 0.01) than that observed during the first 18 hours of the day. The late effects of acebutolol did not change significantly from its early effects. The two agents also differed in their trough (final 2-hour decrease in diastolic BP) and peak (maximum 2-hour decrease in diastolic BP) effects: for atenolol the peak-to-trough difference was 7.8 +/- 3.1 mm Hg (p less than 0.05), whereas for acebutolol it was 3.8 +/- 4.2 mm Hg (N.S.). This study confirms the efficacy of atenolol and acebutolol.(ABSTRACT TRUNCATED AT 250 WORDS)

Accuracy of a piezoelectric crystal microphone interfaced through an audio amplifier board for use in an automated blood pressure device

Two certified blood pressure technicians and a computerized blood pressure monitor from Computerized Screening, Inc., model 2000 (CSI 2000) obtained 900 blood pressure (BP) readings from 100 subjects aged 15 to 85 years (mean = 44.1 +/- 1.8 SEM). Measurements were obtained simultaneously on the same limb by the observers and the CSI 2000 three times per subject within a 30-minute period). Pressures obtained from the CSI 2000, which uses a piezoelectric crystal microphone interfaced through a newly designed audio amplifier board, were compared with the results of indirect cuff mercury sphygmomanometry. Correlations between the CSI 2000 readings and simultaneous readings obtained by two certified BP technicians for systolic and diastolic BP were r = 0.96 (p less than 0.001) and r = 0.91 (p less than 0.001), respectively. For systolic BP readings, the estimating equation (least-squares) based on a linear relationship between measurements from the test and reference methods was: CSI 2000 systolic BP = -3.454 + [1.015 x (observers' systolic BP)]. For diastolic BP readings, the estimating equation (least squares) was: CSI 2000 = 5.997 + [0.906 x (observers' diastolic BP)]. Close agreement was found between the readings obtained by the CSI 2000 and the average of those obtained by the two certified BP technicians.

Enhanced blood pressure response to regular daily stress in urban hypertensive men

Twenty-eight urban untreated hypertensive men (mean age: 54 years; systolic (SBP)/diastolic (DBP) blood pressure at clinic: 148/96 mmHg] and 26 age- and sex-matched normal controls (54 years, 118/78 mmHg) were examined during normal daily activities by ambulatory blood pressure monitoring. When compared with home blood pressures, clinic blood pressures were 8/10% (SBP/DBP) higher in the hypertensives, but 1/3% lower in the normotensives. The values were significantly different for both groups (P less than 0.01 for SBP; P less than 0.001 for DBP). In contrast, the blood pressures fell in a similar manner in both groups during sleep. On working days, the blood pressures during work were 10/9% higher than the corresponding home blood pressures in the hypertensives and only 3/3% higher in the normotensives. These differences were significant (P less than 0.01 for both SBP and DBP). The results show that the blood pressures of hypertensives were hyperreactive to casual daily stress. In the normotensives, left ventricular wall thickness determined by echocardiography was correlated significantly with the blood pressures during work (r = 0.5, P less than 0.05 for SBP and DBP) and at home (r = 0.4, P less than 0.05 for SBP).

Parkinson's disease and hypotension: 24-hour blood pressure recording in ambulant patients

Continuous intra-arterial blood pressure was recorded in 5 ambulatory patients with Parkinson's disease and in 5 control subjects. The 24-h mean systolic blood pressure was 135 +/- 7.6 mmHg in controls and 123.8 +/- 8.1 mmHg (p less than 0.01) in the parkinsonian group. Similarly, diastolic blood pressure was 89 +/- 8.1 mmHg in the control group while in the parkinsonian patients it was lower, 69.4 +/- 5.8 (p less than 0.01). Averages were also calculated for 8-h periods, the results of which indicate that both systolic and diastolic blood pressure were significantly lower in patients than in controls in all three 8-h periods of the day. We normalized the blood pressure curve to mealtimes and arousal times and did not observe any difference between parkinsonian patients and controls. This first study reporting continuous intra-arterial blood pressure measurements in ambulant parkinsonian patients demonstrates that blood pressure in such patients is lower than the mean for their age group. This finding may be of direct relevance in the management of idiopathic parkinsonism.

[Critical analysis of the response to antihypertensive therapy. Report of 102 cases]

One hundred and two patients with mild to moderate hypertension, non responding to a placebo therapy, were given an antihypertensive drug for a mean period of 6 weeks (range: 3-12 weeks). Their blood pressure (BP) was measured before and after active treatment by both a mercury manometer at the clinic and an ambulatory apparatus (Spacelabs 5200 or 90202). The clinic BP figures were poorly correlated with the 24 hour ambulatory BP levels, as well as the magnitude of decrease in clinic BP with the reduction in ambulatory BP. Twenty eight patients who were considered as "clinic responders" had in fact not significantly lowered their ambulatory DBP and, conversely, 16 patients were "clinic non responders" whereas they were "ambulatory responders". The patients were divided into 2 groups, according to White's and Morgan Roth's recommendations: group I (n = 61) with a percentage of pathological DBP readings (greater than 90 mmHg) during daytime as high as 50% or more, and group II (n = 41) with a percentage less than 50%. The correlations between the 2 methods of BP measurement were closer within the group I than within the group II and the rate of discrepancies between the "clinic" and "ambulatory responders" was lower. On the other hand, we identified the group II patients as being often "clinic responders" but rarely "ambulatory responders", whereas the inverse trend was observed in the group I.

IN CONCLUSION

even in non placebo responding hypertensive patients the clinic BP measurement might be not sufficient for proper evaluation of an antihypertensive drug.(ABSTRACT TRUNCATED AT 250 WORDS)

[Ambulatory blood pressure in hypertension with dysautonomia]

The purpose of the study was to evaluate the interest of ambulatory blood pressure (BP) recording (ABPR) in the management of arterial hypertension (AH) with dysautonomia. The study concerned 8 hypertensive patients (pts), 5 men, 3 females 52 +/- 10 years old, with orthostatic hypotension (OH): BP was 162 +/- 19/87 +/- 16 mmHg and 129 +/- 15/76 +/- 8 mmHg in lying and standing position respectively. In two cases AH was associated with a central degenerative disorder whereas the six other pts had a diabetic dysautonomia: bad metabolic control (HBA1c 14.4 +/- 2.7%), and incipient or over nephropathy (4 pts). ABPR was performed in all pts during 24 hours (space-labs system). In these hypertensive pts with OH, the mean 24 hour-BP was surprisingly normal at 128 +/- 11/76 +/- 6 mmHg. ABPR demonstrated the loss of nocturnal decline in BP: diurnal and nocturnal BP were respectively 125 +/- 13/74 +/- 6 mmHg and 133 +/- 16/78 +/- 10 mmHg (NS). 6 of 8 pts had an increase in BP at night resulting for the population (n = 8) in a nocturnal increase (%) of + 5.6%, this pattern widely differs from controls--13%. The decrease in heart rate during sleep was blunted but significant from 89 +/- 9 b/min to 81 +/- 9 b/min (p 0.01). Diurnal and nocturnal BP variability (V), assessed by variation coefficient were not significantly different: SBP-V was 10.3 +/- 6.4% day and 12.3 +/- 4.2% night, DBP-V 7.5 +/- 6.3% day and 12.5 +/- 3.1% night.(ABSTRACT TRUNCATED AT 250 WORDS)

[Blood pressure variability and morbidity]

In a previous study (resting blood pressure profile, Dinamap) we have confirmed the correlations between blood pressure and left ventricular mass (myocardial hypertrophy being one of the morbidity criteria in Hypertension) and we have demonstrated the absence of significant difference (Fisher's z Test) with the results of ambulatory recordings found in literature. Furthermore, we have showed a weaker correlation between absolute variability (AV) and left ventricular mass (LVM). If indeed there exists a cause-effect relationship between the AV increase and the LVM increase, a relative independence between VA and blood pressures mean (mBP) should still be demonstrated. In order to do that we have used the factorial analysis (main components analysis) with which a small number of independent factors can be isolated from a large number of correlated variables. A resting blood pressure (Dinamap, 8AM-8PM, one reading every 15 minutes) has been recorded among 551 patients (259 females, 292 males; 109 normotensive WHO, 442 hypertensive WHO) and an echocardiogram TM and two-dimensional in order to measure the interventricular septum thickness (IVST), the posterior wall thickness (PWT) and the left ventricular internal diameter (LVID) with which we can calculate the myocardial mass (MM, Devereux formula) and the myocardial mass index (MMI) using the body surface (BS). The blood pressure variables are the means of the recordings (mBP): systolic (mSBP), diastolic (mDBP), mean (mMBP) and their standard deviations (SSD, DSD, MSD) corresponding to the AV. We have studied the heart rate (HR) with its standard deviation (HRSD) and age.(ABSTRACT TRUNCATED AT 250 WORDS)

[Microalbuminuria, an early marker of renal changes in essential hypertension]

The purpose of this study was to verify if microalbuminuria (AER) could be an early feature of renal hemodynamic changes in essential hypertension. Fifty-three patients with newly diagnosed essential hypertension (EH) underwent 24-hour blood pressure monitoring (24h-BP). Furthermore, AER and glomerular filtration rate (GFR) were evaluated by obtaining 24-hour urine collection: day- and night-time urine was kept separate. Data from the 53 EH patients were analyzed both collectively and after subdivision into two subgroups based on AER values (less or more than 16 micrograms/min). In the 53 EH patients, 24h-AER correlated significantly to both 24h systolic and diastolic blood pressure (BP) (r = 0.58 and 0.67, respectively). The subgroup with AER greater than 16 micrograms/min showed higher values of 24h-BP and GFR than the other subgroup. Moreover, in the first subgroup, 24h-systolic BP (r = 0.61) and 24h-diastolic BP (r = 0.68) correlated with AER. Our data seem to indicate that among the hypertensive patients, there is a subgroup of subjects whose hypertensive disease is characterized by high blood pressure as well as elevated microalbuminuria and glomerular filtration rate values. Increased microalbuminuria in newly diagnosed hypertensive disease seems to be due to glomerular hypertension and early altered microvascular permselectivity, and would thus indicate an early clinical expression of altered renal hemodynamics.

[A comparative study of the effects of lisinopril and quinapril administered once a day in essential hypertension]

The aim of the study was to compare efficacy and safety of quinapril and lisinopril once-daily administered in patients with mild to moderate hypertension. After a two-week placebo period, 23 patients with sitting diastolic blood pressure between 95 and 110 mmHg were randomly assigned to the therapy with quinapril 20 mg/die or lisinopril 10 mg/die for 4 weeks in a single-blind design. After 4 weeks patients with diastolic blood pressure greater than 90 mmHg were treated with a higher dose (lisinopril 20 mg/die; quinapril 40 mg/die). Therapy with lisinopril normalized 83% of patients, and quinapril 45% of patients. Lisinopril was significantly better than quinapril in reducing blood pressure after 4 and 8 weeks of active treatment. The 24 hours ambulatory blood pressure monitoring showed that quinapril failed to control blood pressure after 12 hours from the administration of the drug.

[The continuous recording of ambulatory arterial pressure. The value of monitoring 4-hour subperiods]

The ambulatory continuous arterial pressure monitoring permits a more exact definition of the degree of arterial hypertension. A ACMPA was performed in 86 subjects, 64 hypertensive and 22 normotensive controls during a daytime period of 16 hour with a noninvasive device. The results were compared to those obtained in the four four-hour subperiods. The correlation of each subperiod with the global studied period was: r = 0.915; subperiod 16-19 hours, r = 0.933; subperiod 20-23 hours, r = 0.924. It was observed that in any four-hour subperiod was quite similar to the mean value of the whole period. We conclude that in those cases in which it is not possible to perform a 24 hour ACMAP or during the whole daytime, a short four-hour monitoring is valid.

Relaxation therapy and continuous ambulatory blood pressure in mild hypertension: a controlled study

OBJECTIVE

To determine the long term effects of relaxation therapy on 24 hour ambulatory intra-arterial blood pressure in patients with mild untreated and uncomplicated hypertension.

DESIGN

Four week screening period followed by randomisation to receive either relaxation therapy or non-specific counselling for one year. Ambulatory intra-arterial blood pressure was measured before and after treatment.

SETTING

Outpatient clinic in Amsterdam's university hospital.

SUBJECTS

35 Subjects aged 20-60 who were being treated by general practitioners for hypertension but were referred to take part in the study. At three consecutive screening visits all subjects had a diastolic blood pressure without treatment of 95-110 mm Hg. Subjects were excluded if they had damaged target organs, secondary hypertension, diabetes mellitus, a cholesterol concentration greater than 8 mmol/l, or a history of malignant hypertension.

INTERVENTIONS

The group allocated to relaxation therapy was trained for eight weeks (one hour a week) in muscle relaxation, yoga exercises, and stress management and continued exercising twice daily for one year with monthly visits to the clinic. The control group had the same attendance schedule but had no training and were requested just to sit and relax twice a day. All subjects were asked not to change their diet or physical activity.

MAIN OUTCOME MEASURE

Changes in ambulatory intra-arterial blood pressure after one year of relaxation therapy or non-specific counselling.

RESULTS

Mean urinary sodium excretion, serum concentration of cholesterol, and body weight did not change in either group. Diastolic pressures measured by sphygmomanometry were 2 and 3 mm Hg lower in subjects in the relaxation group and control group respectively at the one year follow up compared with initial readings. The mean diastolic ambulatory intra-arterial pressure during the daytime had not changed after one year in either group, but small treatment effects could not be excluded: the mean change for the relaxation group was -1 mm Hg (95% confidence interval -6 to 3.9 mm Hg) and for the control group -0.4 mm Hg (-5.3 to 4.6 mm Hg). Mean ambulatory pressure in the evening also had not changed over the year, and in both groups nighttime pressure was 5 mm Hg higher. The variability in blood pressure was the same at both measurements.

CONCLUSIONS

Relaxation therapy was an ineffective method of lowering 24 hour blood pressure, being no more beneficial than non-specific advice, support, and reassurance--themselves ineffective as a treatment for hypertension.

Twenty-four-hour blood pressure monitoring and effects of indapamide

Twenty-four-hour blood pressure (BP) monitoring with a noninvasive device (Kontron) has been used to assess the effect of a single dose of indapamide in a group of patients with essential hypertension. Originally 23 patients were selected. Three patients withdrew from the study because of refusal to go through the second 24-hour recording. Eight of the remaining patients had to be excluded for technical reasons, which left 12 patients available for analysis. All patients received a single dose of indapamide, 2.5 mg/day. Before treatment began, a 24-hour BP control was performed, and a second one a month later (37 +/- 8 days). The age of the patients was 46 +/- 10 years. Diurnal BP (8 am to 10 pm) and heart rate were, respectively, 148 +/- 15/101 +/- 6 mmHg and 79 +/- 9 beats/min; night BP (10 pm to 8 am) was 131 +/- 15/88 +/- 7 mmHg and heart rate 71 +/- 10 beats/min. After therapy, diurnal BP was 131 +/- 15/92 +/- 7 mmHg (-15 +/- 7/-8 +/- 4: p less than 0.0001/p less than 0.0001); heart rate 82 +/- 8 beats/min (difference not significant); night BP was 115 +/- 13/80 +/- 8 mmHg (-16 +/- 11/-8 +/- 7: p less than 0.0001/p less than 0.0001) and heart rate 70 +/- 9 beats/min (difference not significant). Twenty-four-hour systolic work values were 106 +/- 15 at the beginning of the trial and 96 +/- 14 (-9.7 +/- 14; p less than 0.05) after 1 month of indapamide treatment. Variability did not change with treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

Blood pressure increases, birth weight-dependent stability boundary, and intraventricular hemorrhage

The blood pressure (BP) and transcutaneous PO2 (TcPO2) changes associated with intensive care procedures were evaluated to determine whether responses differ between babies with and without periventricular-intraventricular hemorrhage (PV-IVH). Fifty-three inborn babies less than or equal to 1500 g were studied using a microcomputer-based monitoring system. With almost any procedure including a seemingly benign one such as a diaper change, peak systolic BP increased and TcPO2 decreased. However, responses to interventions did not differ between babies with PV-IVH and those without PV-IVH. Neither did these responses differ between those with birth weight less than or equal to 1000 g and greater than 1000 g. When each baby's record was scanned for the highest peak systolic BP before diagnosis of PV-IVH or within 48 hours in those with no PV-IVH and their BP points plotted against birth weight, a stable region was evident wherein PV-IVH occurred at a lower incidence (13%). When peak systolic BP was beyond this stable region, the incidence of PV-IVH was significantly higher, 70% (P less than .0001). The stability boundary for the maximum systolic BP is birth weight-dependent; the limit for the highest tolerable peak systolic BP is lower for the low-birth-weight infant. In over 70% of instances the highest peak systolic BP was associated with motor activities either induced by nursery procedures or spontaneous. We speculate that decreasing the frequency of intensive care interventions may decrease episodic BP increases to levels beyond the birth weight-dependent stability boundary where PV-IVH is likely to occur.

[Doctor's-office blood pressure, home blood pressure, ergometry blood pressure and 24-hour blood pressure. The correlations with the echocardiographic parameters of heart muscle mass]

In 62 untreated hypertensives (31 men, 31 women; median age 40 [17-57] years) blood pressures (BP) were measured in the doctor's office, at home (self-measured) and every 15 min during 24-hour monitoring (by portable automated oscillometry), the results being compared with echocardiographic measurements of ventricular septal thickness (VST), left ventricular muscle mass (LVM) and left ventricular mass index (LVMI), in 41 of them also during and 5 min after 100 W bicycle ergometry. In the total cohort, 24-hour values correlated better with diastolic VST (systolic: r = 0.706, P less than 0.00001; diastolic: r = 0.507, P less than 0.0001) than office BP (systolic: r = 0.381, P less than 0.01; diastolic: r = 0.177, not significant) and home BP (systolic: r = 0.477, P less than 0.0001; diastolic: r = 0.371, P less than 0.05). In the 41 exercised hypertensives the correlation with echocardiographic values was less close than with their 24-hour BP, but slightly better than with office and home BP. Systolic BP correlated better than diastolic BP with echocardiographic values. VST generally correlated better with BP than LVM and LVMI. It is concluded that (1) 24-hour BP values correlate more closely with LVM than any other noninvasive BP measurement; (2) VST is affected more by systolic than diastolic BP; and (3) VST more specifically reflects the influence of BP on myocardial structure than does LVM and LVMI.

Determination of clinical accuracy and nocturnal blood pressure pattern by new portable device for monitoring indirect ambulatory blood pressure

The accuracy and clinical application of a new portable device for measuring ambulatory blood pressure (BP) (ABPM 630, Nippon Colin, Nagoya, Japan) were assessed. The device uses a conventional arm cuff inflated by CO2 gas from a compact cartridge and is based on a cuff-oscillometric as well as a Korotkoff sound (microphone) technique. Blood pressure values obtained by ABPM 630 were compared with those measured by the auscultatory method. With the microphone method the mean differences from the auscultatory method were -0.28 +/- 6.15 mm Hg (mean +/- SD) for SBP and 0.96 +/- 6.28 mm Hg for DBP (n = 256), while for the cuff-oscillometric method the mean differences were -1.77 +/- 6.07 mm Hg for SBP and 3.06 +/- 6.87 mm Hg for DBP (n = 297). There was a highly significant correlation between BP values measured by the auscultatory method and ABPM 630. In 40 untreated subjects, 24 h BP was monitored simultaneously with the ABPM 630 and with a finger volume-oscillometric device (UBP-100, UEDA, Tokyo, Japan). The daytime average of SBP with the former (126 +/- 11.6 mm Hg) was almost the same as that with the latter (123 +/- 16.0 mm Hg), while the nighttime average in the former (117 +/- 9.7 mm Hg) was significantly higher than that in the latter (108 +/- 14.1 mm Hg, P less than .01). Only 4 out of 40 subjects experienced no sleep disturbance from the arm-cuff inflation. Five of the 40 subjects complained that their sleep was frequently interrupted by the arm-cuff inflation.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of regular alcohol consumption on 24 hour ambulatory blood pressure recordings

1. Regular consumption of 1 g/kg of alcohol for 4 days did not significantly alter mean 24 h blood pressures compared with a similar period when dextrose was consumed to match caloric intake. 2. In contrast, the variability of diastolic blood pressure was increased by regular alcohol consumption. 3. Increased blood pressure variability in response to the stress of blood pressure measurement may contribute to the observed association between hypertension and alcohol consumption.

[Monitored and random arterial blood pressure as prediction of biological risk. Comparison with domiciliary self-measurement]

The approach to the hypertensive patient is still a subject of debate. The use of new measurement methods permits us to obtain more exact blood pressure values which represent an index of cardiovascular condition. We also demonstrated that non-invasive monitoring and self-measurement at home consent better management of hypertension.

Ambulatory blood pressure monitoring in hypertensive adolescents

The purpose of this study was to determine the ability of ambulatory blood pressure monitoring to identify youths with chronic blood pressure elevation. Nineteen adolescent boys were studied, ten had 5-year average systolic or diastolic pressures above the 95th percentile, nine had normal pressure. A Del Mar Avionics Pressurometer III system recorded an average of 121 readings on each subject. The coefficients of variation for pressure were similar for hypertensive and normotensive individuals. During classes, eight of the ten hypertensive youths had elevated pressures in over half of the measurements. Also during these classes eight of ten hypertensive boys had average systolic or diastolic pressure above the 95th percentile, whereas only one of nine normotensive boys had average pressures above this level. We suggest that schooltime ambulatory pressures may be most useful in classifying the blood pressure trend in a youth.

[Borderline arterial hypertension in young adults: contribution of paraclinical investigations]

The comparison of 106 young adults with borderline hypertension to 85 controls allow to specify the contribution of paraclinic investigations in the diagnosis. Ambulatory blood pressure monitoring reveal the lack of lability of borderline hypertensives and cannot find predictive index of subsequent established hypertension. Results of exercise testing disclose correlation only with overweight. It is the same for increased left ventricular mass assessed by echography. Pulse wave velocity measurement display early arterial modifications.

An 'admission challenge test' to predict severe hypertension in pregnancy?

Although many pregnant women are admitted to hospital for 'high blood pressure' during the third trimester, less than a third of them will subsequently develop severe hypertension. We used a Dinamap 1846 vital signs monitor to measure the blood pressure every 5 min during the first hour in hospital of a group of 51 previously normotensive pregnant women admitted with hypertension. An average systolic pressure at or above 140 mmHg was recorded in 37% of patients and, of these, 68% went on to develop severe hypertension. Conversely, if the average systolic pressure on admission was below 140 mmHg, only 3% of patients later developed severe hypertension. In terms of sensitivity, specificity, and positive and negative predictive values of severe hypertension, the 1-hour automated blood pressure profile was superior to conventional measurements whether they were made prior to admission, on admission, or during the first 24 hours after admission.

[Morning rise in blood pressure: before or following awakening?]

The coincidence of the circadian peak of cardiovascular events with the morning blood pressure rise suggests causal connections. Rapidly acting antihypertensives taken before getting up may attenuate the increase early enough, if the onset does not occur before awakening. In 111 normotensives and in 109 subjects with untreated essential hypertension ambulatory blood pressure monitoring was performed to study whether the onset of the blood pressure rise occurs before or after waking up. The individual 24 h blood pressure profiles obtained by intermittent readings at intervals of 15 minutes were synchronized by the time of waking up. The resulting blood pressure curves showed no substantial blood pressure rise during sleep, but steep increases after awakening: Within the first hour after waking up blood pressure increased from 107.3 + 11.4/62.3 +/- 9.6 mm Hg (mean + sd) to 121.4 +/- 16.0/75.3 + 12.6 mm Hg in normotension and from 124.7 + 16.0/72.7 + 12.2 mm Hg to 140.3 + 17.2/84.5 + 13.3 mm Hg in hypertension. The velocity of this increase was dependent on the lag between waking up and getting up. There was no phase difference between early morning blood pressure and heart rate rises. Thus to attenuate the morning blood pressure increase, rapidly acting drugs after awakening may be considered instead of long acting antihypertensives administered prior to sleep.

Non-invasive continuous finger blood pressure measurement during orthostatic stress compared to intra-arterial pressure

STUDY OBJECTIVE

The aim of the study was to evaluate whether invasive blood pressure responses to orthostatic stress can be replaced by non-invasive continuous finger blood pressure responses. DESIGN - Intrabrachial and Finapres blood pressures were simultaneously measured during passive head up tilt and during active standing from the supine or sitting position in healthy volunteers.

SUBJECTS

Subjects (n = 11) were healthy males aged 22-40 years, mean age 30 years.

MEASUREMENTS AND MAIN RESULTS

Beat to beat values of systolic, diastolic, and mean arterial pressures were calculated for both methods of measurement and the differences compared during a 30 s control period before, and during the first 120 s after, the change of posture. In the control period the difference between finger pressure and intra-arterial pressure was +2 (SD11) mm Hg for systolic, -4(8) mm Hg for mean, and -3(7) mm Hg for diastolic pressure. Compared to these control differences, the average finger minus intra-arterial pressure differences for mean and diastolic pressures during the three orthostatic manoeuvres were always within the range -6 to +6 mm Hg. The average systolic deviations were larger, ranging from -10 to +11 mm Hg. Despite these differences the characteristic changes in intra-arterial pressure during the initial phase (first 30 s after change of posture), as well as during the early steady state phase (1-2 min after the change of posture) were well reflected by finger pressure measurements in all subjects.

CONCLUSIONS

For the assessment of the continuous blood pressure responses to orthostatic stress similar information can be obtained with non-invasive Finapres blood pressure recordings as with invasive recordings.

[Clinical significance of nocturnal blood pressure and blood pressure variability: analysis of 522 cases]

Purpose of the study was to investigate whether and to what extent blood pressure variability and average night-time blood pressure are related to cardiovascular complications in hypertension. To this aim 60 normotensive and 462 hypertensive subjects were studied by means of non-invasive 24 hour blood pressure monitoring, using either the Avionics, or the ICR Spacelabs, or the Takeda system. Each subject was attributed a target organ damage score on the basis of 12-lead electrocardiogram, chest X-ray and fundoscopy, starting from 0 (no damage) up to 5 (maximum degree of damage). The 522 subjects were subsequently subdivided into 5 classes of increasing average daytime diastolic blood pressure. In each class a higher degree of cardiovascular complications was present in the subjects with the higher blood pressure variability and the higher average night-time blood pressure. From these results it may be inferred that both blood pressure variability and night-time blood pressure are related to the degree of target organ damage in hypertension. This stresses the importance of recording blood pressure throughout the 24 hours.

Antihypertensive effect of isradipine administered once or twice daily on ambulatory blood pressure

The antihypertensive efficacy of sustained-release isradipine administered once daily compared to the immediate-release formulation administered twice daily was assessed by ambulatory blood pressure (BP) monitoring in a double-blind randomized crossover study in 76 mild-to-moderate hypertensive patients. Conventional BP and heart rate parameters were evaluated after a 4-week placebo period and patients qualified for entry if sitting diastolic BP was between 95 and 114 mm Hg. Ambulatory BP monitoring was measured at baseline and after active treatment with both formulations. The 2 regimens induced a significant and almost identical reduction (p less than 0.001) in the mean 24-hour BP without affecting heart rate. Isradipine was more effective in patients whose clinical hypertension was confirmed by ambulatory BP monitoring (35) than in patients who remained normotensive by ambulatory BP monitoring criteria (41). The isradipine-treated ambulatory hypertensive group experienced significantly greater decreases in BP during 24-hour, work, awake and sleep periods than did the ambulatory normotensive group. These data suggest that sustained-release isradipine has a sustained antihypertensive effect throughout 24 hours comparable to that of isradipine given twice daily and may improve compliance with long-term treatment. In addition, the results confirm the usefulness of ambulatory BP monitoring in determining truly hypertensive patients likely to respond to drug administration.

[24-hour blood pressure determination in Shy-Drager syndrome. A case report]

The case history is presented of a 57 year-old male patient suffering from the Shy-Drager syndrome. This syndrome was first described by G. M. Shy and G. A. Drager in 1960. The clinical manifestations are extrapyramidal, with Parkinsonian features, combined with severe orthostatic hypotension and failure of the autonomic nervous system. Apart from the standard clinical investigations in this condition, namely the orthostasis test and polygraphic recording of the EEG, ECG, breathing and blood pressure on the tilting table, additional non-invasive long-term determination of the blood pressure was carried out. This method allows simultaneous measurement of blood pressure and heart rate without appreciably interfering with the patient's daily activities.

Continuous 24-hour assessment of the neural regulation of systemic arterial pressure and RR variabilities in ambulant subjects

In this study, we tested the hypothesis that the neural control of circulation in humans undergoes continuous but in part predictable changes throughout the day and night. Dynamic 24-hour recordings were obtained in two groups of ambulant subjects. In 18 hospitalized patients free to move, direct high-fidelity arterial pressures and electrocardiograms were recorded, and in an additional 28 nonhospitalized subjects, only electrocardiograms were obtained. Spectral analysis of systolic arterial pressure and of RR interval variabilities provided quantitative markers of sympathetic and vagal control of the sinus node and of sympathetic modulation of vasomotor tone. With this approach, the low-frequency (approximately 0.1 Hz) component of RR interval and systolic arterial pressure variabilities is considered a marker primarily of sympathetic activity, whereas the high-frequency (approximately 0.25 Hz) component of RR interval variability, related to respiration, seems to be a marker primarily of vagal activity. We observed a pronounced and consistent reduction in the markers of sympathetic activity and an increase in those of vagal activity during the night. In the invasive studies, while the subjects were still lying in bed after waking up, the markers of sympathetic activity rose rapidly and concomitantly with a simultaneous vagal withdrawal. Noninvasive studies confirmed the early morning rise of the markers of sympathetic activity and the circadian pattern of sympathovagal balance. These data indicate that the ominously increased rate of cardiovascular events in the morning hours may reflect the sudden rise of sympathetic activity and the reduction of vagal tone.

Ambulatory blood pressure in normal Chinese

Noninvasive ambulatory blood pressure monitoring (NABPM) has been playing an increasing role in the diagnosis of hypertension and in the evaluation of antihypertensive drugs. NABPM data for the normal Chinese population has not yet been established. However, data obtained from 25 young male Chinese adults has been analysed. Average ambulatory blood pressure was 120 +/- 8/74 +/- 7 mmHg for the whole-day monitoring. There was an evident diurnal change of blood pressure during the 24-hour monitoring period with higher blood pressure levels being recorded during the daytime, rather than during the nighttime (7.8 +/- 9.7/4.4 +/- 4.8 mmHg; p less than 0.001). Maximal hourly blood pressure averages occurred during the late morning, while minimal hourly blood pressure averages occurred around midnight. The variability in blood pressure was 11 +/- 3/9 +/- 2 mmHg for the daytime and 11 +/- 3/8 +/- 2 mmHg for the nighttime. The incidence of abnormally high blood pressure ranged widely. Eating would raise both the systolic and diastolic blood pressure, while sleep caused a significant fall in blood pressure. This study offers basic data for the study of NABPM in young normotensive Chinese adults.

Systolic pressure measurement in the ascending aorta: augmentation at the aortic cannula sideport

To assess whether arterial blood pressure measured at the sideport of the aortic cannula mirrors that measured within the ascending aorta, the two pressures were compared in 10 consecutive patients undergoing cardiopulmonary bypass. The mean arterial pressures (MAP) were equal both before and after bypass, but the sideport systolic arterial pressure (SAP) was 6.0 +/- 0.8 mm Hg higher than the aortic SAP before bypass and 9.1 +/- 0.5 mm Hg higher than the aortic SAP after bypass (P less than 0.001). Hematocrit, blood temperature, cardiac output, and heart rate did not correlate with the differences in SAP, suggesting that the higher SAP seen at the sideport was generated within the tube connecting the oxygenator to the aorta. This theory was investigated by decreasing the tube length distal to the sideport in three patients in this group who had sideport SAPs higher than their aortic SAPs, a measure that decreased the SAP difference between the two sites. At the end of cardiopulmonary bypass in 20 other consecutive patients, the effect of shortening the aorta-oxygenator tube from 1.8 to 0.25 m was tested. The SAP in the sideport decreased by 4 to 12 mm Hg in 12 of the 20 patients, while the MAP was unaffected by this maneuver. It is concluded that the MAP measured at the sideport of the aortic cannula closely reflects the MAP in the ascending aorta, whereas the SAP measured at the sideport does not reflect the aortic SAP. Thus, when aortic pressure is measured at the sideport to confirm an artificially low radial arterial pressure, systolic amplification at the sideport might simulate or exaggerate radial artery hypotension.

Measurement of arterial pressure after cardiopulmonary bypass with long radial artery catheters

Radial arterial pressure can significantly underestimate central aortic pressure in the postcardiopulmonary bypass (post-CPB) period. At the study institution, routine monitoring of perioperative arterial pressure in adult patients undergoing cardiac surgery is performed with a long radial artery catheter with the distal end positioned in the subclavian artery. In 68 patients presenting for elective cardiac surgery, both a conventional short radial artery catheter and a contralateral long radial artery catheter were placed. Analysis of radial and subclavian arterial pressures post-CPB in the first 47 patients showed average maximum differences of 7 mm Hg systolic and 4 mm Hg mean. In 15% of patients, the differences were clinically significant (greater than 20 mm Hg systolic and/or greater than 14 mm Hg mean). In 28 patients, central aortic pressure was measured post-CPB, and subclavian artery pressure was found to be an excellent estimator of central aortic pressure. There were no significant complications related to using long radial artery catheters in the 68 patients who were followed prospectively. Monitoring subclavian arterial pressure by percutaneous insertion of a long radial artery catheter provides a reliable estimation of central aortic pressure, even in patients with significant radial artery-to-central aortic pressure gradients post-CPB.

Ambulatory blood pressure monitoring and echocardiographic left ventricular wall thickness and mass

In a highly select group of stable hypertensive patients, we have assessed the strength of association between various blood pressure measurements (24 h average automated ambulatory blood pressure, 4 h automated ambulatory morning average blood pressure, multiple office visit average blood pressure, and a single office visit average blood pressure) and various echocardiographic indices of hypertensive cardiac target organ damage (left atrial diameter, left ventricular end diastolic diameter, posterior wall thickness, combined wall thickness, relative wall thickness, left ventricular mass and mass index, and combined wall thickness/left ventricular diastolic diameter ratio). These data demonstrated that a single 24 h average diastolic blood pressure by automatic noninvasive ambulatory monitoring was a significantly better predictor of echocardiographic posterior wall thickness, combined wall thickness or relative wall thickness than the multiple office or single office average diastolic blood pressure. Also there were highly significant correlations between both 24 h average systolic and diastolic blood pressure and these echocardiographic parameters (in descending order of correlation coefficient): combined wall thickness, posterior wall thickness, combined wall thickness/left ventricular diastolic diameter, left ventricular mass index, relative wall thickness, and left ventricular mass. Left ventricular end diastolic dimension did not linearly correlate with any systolic or diastolic blood pressure measurement. Left atrial dimension demonstrated only a significant association with 24 h average diastolic blood pressure. Single office average blood pressure did not linearly correlate with any echocardiographic parameter.(ABSTRACT TRUNCATED AT 250 WORDS)

Circadian blood pressure changes and left ventricular hypertrophy in essential hypertension

The effects of circadian blood pressure (BP) changes on the echocardiographic parameters of left ventricular (LV) hypertrophy were investigated in 235 consecutive subjects (137 unselected untreated patients with essential hypertension and 98 healthy normotensive subjects) who underwent 24-hour noninvasive ambulatory blood pressure monitoring (ABPM) and cross-sectional and M-mode echocardiography. In the hypertensive group, LV mass index correlated with nighttime (8:00 PM to 6:00 AM) systolic (r = 0.51) and diastolic (r = 0.35) blood pressure more closely than with daytime (6:00 AM to 8:00 PM) systolic (r = 0.38) and diastolic (r = 0.20) BP, or with casual systolic (r = 0.33) and diastolic (r = 0.27) BP. Hypertensive patients were divided into two groups by presence (group 1) and absence (group 2) of a reduction of both systolic and diastolic BP during the night by an average of more than 10% of the daytime pressure. Casual BP, ambulatory daytime systolic and diastolic BP, sex, body surface area, duration of hypertension, prevalence of diabetes, quantity of sleep during monitoring, funduscopic changes, and serum creatinine did not differ between the two groups. LV mass index, after adjustment for the age, the sex, the height, and the daytime BP differences between the two groups (analysis of covariance) was 82.4 g/m2 in the normotensive patient group, 83.5 g/m2 in hypertensive patients of group 1 and 98.3 g/m2 in hypertensive patients of group 2 (normotensive patients vs. group 1, p = NS; group 1 vs. group 2, p = 0.002).(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of 24-hour ambulatory blood pressure monitoring on daily activities

Compared the self-monitored activities, locations, and postural positions of 28 hypertensives while they wore an alarm watch and then while they wore a 24-hr ambulatory blood pressure monitor (ABPM) to see if wearing the ABPM led to alterations in behavior. Within the limitations of the study (no counterbalancing of order and twice as many ABPM measures as watch measures), we found significant differences in frequency of being at home or in miscellaneous settings, in standing and reclining positions, and in mental, physical and miscellaneous activities between the two occasions.

Problems and solutions in diagnosing systemic hypertension

The accurate measurement of blood pressure is the bedrock of the proper management of disorders of arterial pressure. This is especially important as hypertension is a prevalent disease, with very considerable impact on morbidity and mortality. Pitfalls in the measurement of blood pressure occur in three main areas: blood pressure measurement devices, blood pressure measurement technique, and blood pressure sampling pattern. Ignorance concerning these areas leads to errors of diagnosis, particularly overdiagnosis in persons with borderline or labile blood pressure. By contrast, skilful application of blood pressure measuring devices will increase one's understanding of blood pressure physiology, pathology, and response to treatment.

Hypertension: role of the nurse-therapist

In this article, we describe the evolution of the hypertension nurse-therapist program at the Mayo Clinic. Because of the large numbers of patients in whom hypertension is a major risk factor for cardiovascular disease, a leading cause of death in the United States and other industrialized nations, an approach was devised in which, with physician supervision, specially trained nurses managed many aspects of the acute and long-term outpatient care of hypertensive patients. Clinical trials in which nonphysician care-providers were used to treat hypertensive patients and to maintain long-term blood pressure control provided an opportunity to identify and to expand the concept of continuing care for blood pressure management in a community hypertension clinic. Currently, almost 7,000 patient visits are scheduled annually in this program, and these patients are seen by five full-time hypertension nurse-therapists.

Pulmonary artery pressure changes during exercise and daily activities in chronic heart failure

Long-term continuous pulmonary artery pressure monitoring was used to investigate pressure changes during different types of exercise and normal daily activities in patients with chronic heart failure. Nine men (mean age 55 years) with treated chronic heart failure underwent continuous pulmonary artery pressure measurement with use of a micromanometer-tipped catheter with in vivo calibration and frequency-modulated recording. The mean (+/- SD) maximal systolic pulmonary artery pressure (in mm Hg) was 59.4 +/- 26.1 on treadmill exercise, 54.9 +/- 30.6 on bicycle exercise, 52.5 +/- 26.1 walking up and down stairs and 43.5 +/- 23.9 walking on a flat surface. The mean maximal diastolic pressure (in mm Hg) was 27.8 +/- 14.6 on treadmill exercise, 25.5 +/- 14.9 on bicycle exercise, 24.9 +/- 14.8 walking up and down stairs and 20.4 +/- 12.5 walking on a flat surface. The increase in pulmonary artery pressure did not correlate with the severity of the limiting symptoms except during walking on a flat surface. All patients had marked postural changes in pressure, with the systolic pressure difference from lying to standing ranging from 8 to 25 mm Hg and the diastolic pressure difference ranging from 3 to 13 mm Hg. Eating meals caused an increase in pressure in three patients, but less than that when lying flat. There was an increase in pressure during urination in four patients equal to that when walking on a flat surface. None of these activities was associated with symptoms. Neither symptoms nor pulmonary artery pressure during maximal exercise is the same as during daily activities. This may restrict the value of maximal exercise tests in assessing patients with chronic heart failure.

[Evaluation of antihypertensive therapy by ambulatory blood pressure monitoring and establishment of the level of antihypertensive goal on the circadian rhythm of blood pressure]

We have developed a new method for the evaluation of antihypertensive therapy on the circadian rhythm of blood pressure and attempted to determine the indications for antihypertensive therapy and the level of antihypertensive goal. Blood pressures were measured for 24 hours by the use of ambulatory blood pressure monitoring using 630 (ABPM-630) in 50 normotensives, 50 untreated hypertensives and 50 hypertensives undertreatment with various antihypertensive drugs (110 males and 40 females, with a mean age of 53.4 +/- 13.3 yrs). Blood pressure profiles were prepared for determination of the hyperbaric and hypobaric indexes. According to the WHO's definitions for blood pressure, the hyperbaric index was defined as the area above 140 mmHg in systolic blood pressure or 90 mmHg in diastolic blood pressure, and the hypobaric index, as the area below 100 mmHg or 60 mmHg, respectively. The criteria of the hypobaric index was obtained from the mean basal blood pressure (the lowest blood pressure during sleep) of the 50 normotensives. The mean hyperbaric index of the 50 normotensives was 20.4 +/- 40.2/5.5 +/- 15.3 (systole/diastole) mmHg.hour/day and the mean hypobaric index, 12.2 +/- 22.5/9.0 +/- 24.0 mmHg.hour/day. The 50 untreated hypertensives showed a mean hyperbaric index of 281.8 +/- 197.0/156.0 +/- 126.1 mmHg.hour/day and a mean hypobaric index of 0.1 +/- 0.6/0.3 +/- 1.5 mmHg.hour/day. Comparison of the indexes before and after treatment with various antihypertensives showed that a decrease in the hyperbaric index without an increase in the hypobaric index was the most optimal reduction of blood pressure.(ABSTRACT TRUNCATED AT 250 WORDS)

Does measurement of systolic blood pressure with a pulse oximeter correlate with conventional methods?

The pulse oximeter is commonly used in the operating room. We evaluated the use of a pulse oximeter to monitor systolic blood pressure in 20 healthy volunteers and 42 anesthetized patients. We compared the pulse oximeter method of measuring systolic blood pressure with the cuff methods using Korotkoff sounds and Doppler ultrasound as well as with direct pressure measurement through an intraarterial cannula. Systolic blood pressure values obtained by pulse oximeter correlated well with values obtained by other conventional methods. The best correlation was found with Doppler ultrasound (r = 0.996) and the worst with arterial cannulation (r = 0.880). We conclude that this method can be used intraoperatively to measure systolic blood pressure.

Intravascular microcatheter pressure monitoring: experimental results and early clinical evaluation

With the use of Tracker and Balt microcatheter systems, intravascular pressure measurements were obtained in an experimental animal model, establishing the reliability of mean blood pressure measurements from these microcatheter systems. In the experimental model, selective occlusion of branches of the external carotid artery with simultaneous pressure measurements showed significant and reproducible changes in intravascular pressures. Also, pharmacologic manipulation of the blood pressure with simultaneous microcatheter and 6-French catheter recordings demonstrated an accurate and linear response of the microcatheter systems to mean blood pressure as it varied from 30 to 130 mm Hg. Preliminary results in humans with vascular malformations yielded similar results. We studied two cases of brain arteriovenous malformations (AVMs), one sigmoid-transverse sinus dural AVM, and one brain arteriovenous fistula (AVF). In these four cases the pressure dropped substantially, approaching the level of the shunt. In the case of the brain AVF, pressures rose in the same vessel after embolization. In the case of the dural AVM, correlation of the venous pouch pressures and the angiographic appearance indicated that shunting was no longer present when the venous and arterial pressures equalized. This system can be of substantial benefit in the evaluation and therapy of these lesions, and may increase our understanding of the physiology of vascular malformations.

Ambulatory blood pressure monitoring in the evaluation of antihypertensive treatment

Cuff blood pressure measurements by doctors and self blood pressure measurements by patients reflect imprecisely 24-hour or daytime mean blood pressure values. This limits the physician's ability to diagnose the absence or presence of hypertension. It also limits his ability to evaluate the response to non-pharmacologic interventions or antihypertensive drugs. This is a major disadvantage because the prognosis of hypertensive persons depends to a large extent on the blood pressure attained during treatment. Ambulatory blood pressure monitoring is a valid method for assessing the effectiveness of antihypertensive treatment because it allows the physician: (1) to determine whether the initially elevated blood pressure is reduced under the various circumstances of the patient's lifetime; and (2) to exclude that this reduction is associated with hypotensive events that might interfere with organ nutrition and function during the day and night. However, this approach has a cost that makes its use impractical in clinical practice, except in cases in which there are reasons to suspect very low or excessively high blood pressures in conditions that are out of the reach of sphygmomanometry. Furthermore, the prognostic value of on-treatment ambulatory blood pressures is still unknown. On the other hand, studies on new antihypertensive agents derive great benefits from the use of ambulatory blood pressure monitoring. This is emphasized by the fact that the ambulatory blood pressure values are more reproducible than isolated cuff blood pressure values, allowing the number of patients necessary to establish an antihypertensive effect to be reduced. Furthermore, these values are little affected by placebo influences thus permitting simplification of the study design. Finally, sequential analysis of the data obtained provides accurate information on the duration of the antihypertensive effect, and thus on the optimal posology to be adopted. However, ambulatory blood pressure monitoring does have technical problems. In the case of non-invasive monitoring, the ability to measure blood pressure phasic events and variability is limited. Another problem, which is of greater importance, is that non-invasive blood pressure monitoring devices generate a number of artifactual and imprecise readings. These problems cannot be entirely eliminated by editing the blood pressure tracing.

[24-hour blood pressure behavior in patients with untreated and treated hypertension in comparison with normotensive patients]

Blood pressure was continuously monitored over 24 h in 201 patients with mild to moderate essential hypertension using a noninvasive method. Measurements were made both before and after 6 months of antihypertensive treatment and the data were compared to results from 100 normotensive patients. The frequency with which blood pressure values above 140/90 mm Hg occurred during the 24-h period proved to be the most reliable parameter for distinguishing between hypertensive and normotensive profiles. The blood pressures of all patients could be normalized (less than 140/90 mm Hg) on single or combined drug therapy as assessed by casual measurement. However, significant differences were observed between the 24-h profiles of the treated patients and the control group. The mean 24-h blood pressure, the mean day and nighttime blood pressures, the mean hourly pressure, and the frequency of increased blood pressure values were all significantly higher in the patients on medication as compared to the normotensive controls. This would suggest that normotension, as defined by the control group, cannot be attained with antihypertensive medication. In conclusion, 24-h continuous blood pressure monitoring allows a better evaluation of blood pressure profiles and consequently, will be of greater value in assessing cardiovascular risk than occasional random measurements.